Controlling access or entry to services and locations is a frequent problem for businesses, individuals, and others. Traditionally, access has been controlled in many different ways, from stationing a person to monitor the access, to using a lock and key, and many other solutions. In any solution, there is a balancing between the cost of implementing the solution, the burden of implementing the solution, and the success rate of controlling the access, among other considerations. New solutions with low cost, low burden, and high success are always desirable.